SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48d82b176187b07489a2609894645f5acd3651bdc6a0bd0f97ffee7797165556' 
  AND token = '3K0wfCGELMZM6btpX6TwA8WrrT7rmqzK5cKFGLXvgbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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