SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8190f4cfee419f7c5b24d918fb26a7bd5f3e3414b0f552a8da941d8282403f53' 
  AND token = 'cMeM3vKla0tNURoWgZICLr4roYGkGqaA1gViEE3Cqfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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