SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6bfa569df0de448d727e898eeaf701c2ef3d2615230458906f8bcb42b188c05' 
  AND token = '4TisfiFjZ6hGs+Yx+lup7+4u7Dermbay8MszFVq7joM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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