SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '397e96792499153ff01ce24e162f69e26828b0fc870d1674620db196f8c4f24a' 
  AND token = '4SCcUNRM4gCU4gTB/gS0jnNZmDbU7+OoIh5hkrd5TSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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