SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '951690c3267cb6fb1301bea38f0abc7f66dec0bb742e497f7093beb658f227a3' 
  AND token = 'vVLtVekzmGtmuvxC1I2G9Yq7l+AjmPuq5L8sKJz1o0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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