SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '425d102199525f771359ac537ed04b51c5b03d7a4bd2ae7f41f64c84e4119ccd' 
  AND token = 'SqXVnNRHn2LE+FmAdhK8DFb+gjCftVlXmFRbm9L0/vI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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