SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd2a8e2a6142ca257e4bf886c73064648dd477078f58507753f263e74e6905a9' 
  AND token = 'z7dIWuZDDCnWfDz/NjWkwAZsJsewJh9vrMYJzgxlr7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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