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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4c3ad38f3b5c47d3746a3ded0ebbe97b559ae1d247003e60dfd07134ee1386b' 
  AND token = 'CACgbFFDCYGM8evMXuvDPY2sqlx3VH1LJs3Q+dE8PtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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