SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '753f96200503dc31f3f80880160e5e559098d2f5635e61ab82bcc0d6175651c7' 
  AND token = '0mnwsyM/8Bh0vt+ZnVuOwr+YNQ65fggRzjcmqiQ9dhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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