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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e139e5b869aa742a9bcd9dea7036441a879c7f1a6b38b86c84eecea7de1cbe' 
  AND token = 'Lf1JGG5fh8/s6CJ6QtfUxMwBLjmcHQ4hi+H2n6K+1ko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}