SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e489262c12e464cce62997c217810c196a04539fe9f035253bb8ec008fddd51' 
  AND token = 'jaxz+eC+d6fA6vnYYJpZp5XmBVNRAc8A7GlemSJPVGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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