SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ea46909d237a189b4883eb2a61753b5f4d8016438e3003ba1c0a84ad99a5c71' 
  AND token = '/r6770rA2HTnkAyyFrQGYhbWRTFd8Yj1XGrKDaUN7WI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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