SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27d569b0c2c15831a6f81948a376bf62002836dc88993d1a6a025692f983983d' 
  AND token = 'PB9ln6Yz6SGTqRWEr5v4pCR9FUKFBjCVeZd0kELxf9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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