SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '268802168d375a3c1271319f01a01e0c7e7e94cb144aa71988e95a76633deb7a' 
  AND token = 'pOuoLa7RzlXGRffgojC4JklXZuqi5ygghBLxVoKbrmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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