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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baa66b40d7d671847f5ef9d0e8fe0f0cddaeedfb0e0b1355466e9674b6fe2d98' 
  AND token = 'b/aqrLt8Np+gyX5DFHArroegBsTHFTw1DmyeNv8TPu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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