SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8cb15943fc0f94711279b19d80114b61308738260e5aeb330bf25d84968ba81a' 
  AND token = '/23r4LJj47m6ZY0h2ZuDaw5b3Xnd3tKga1UR7zE4xqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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