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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c90a9f90fe6c789171dddba146065ec96987973003269eee07a5c1d2e90902a' 
  AND token = 'OPIwMaLln2fQKZxxmL3tBnk08uNNqWEfu7UDrd5fJiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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