SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23d5f38f147512fa4672f756553c2053529954cdbcaf3dc05530c67651b628fb' 
  AND token = 'F0EQNvzIjOkXb7Qak9cKInWU6/I4dz9Rq7rlImeHfno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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