SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c85b3bfa6966de372f11791be1b7db179d60817ae1545687604052e9ec952a77' 
  AND token = '5V3qvzALxBzLny4Fp+A/mkYobUKu/WzZWwvHk7aMCH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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