SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '39acca6b92c67f5b2fa43e2a54c94a6829d9339fdd193bc80586a636dd21e5fa' 
  AND token = 'JseFUNjfIDFY+BjuIpVv10LO+EfI+q1Daz5DvGhHQj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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