SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '506beba367a81ea2328b8bfdda1f2034e397e6684f012f705be39c3807ce1dc0' 
  AND token = 'hG0pJV8GSiwxPFjtKl9k46k+wW8/BycxIyCAfdESfbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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