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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c504817d78cdbc56f9956db0964820366d47ff2f7864b6542eaae6cd45b52358' 
  AND token = 'Pg8Wm2EcKTuxcjmZ8wpUaFF3SNCMiUU22DhmImN4Ty8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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