SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb8003f2e23280df98373a457eb0e0dbfcff9cf123b2ad5a4b8953ab35a4506a' 
  AND token = 'PX/SdUCME6K9eFJko9TDyFsCtjlNx/uGoEeKgw3dgVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}