SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5793bc8e71302a119f65059924b98f902493c0a549026a656c6ae3f08be024f3' 
  AND token = '2JJdd52q+utP7iKFoOT7In8PnmPRQt0Kc1dmsIKdFd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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