SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9748b1a6969dc98f35a1b07fefef026f449cc62a88db5a42a73739fd0ef1e543' 
  AND token = 'Z50BvwtRzE1roz1WwPWGIdXLoh5iYbITlQ+7pL8nluM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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