SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a19bee8b694cc702dae7f4d4e0c104ff512dc088ab4654ec96a60c614383a52' 
  AND token = 'X56xuohffGtITpbq0ZLyUHzFzlKcL+DIYdEMkve+ZW4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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