SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cacaabddcedffd13a15848b26ee6986b712e842958db15be3b7549c2c3660b4f' 
  AND token = 'oZMRKCbWWHgLXDbdTeUR99WcmnA/SCnkRnZCyra8WIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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