SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e566d73c8075b92dce7497b50b7007049b46c398936aa3f8d461e94898e89f5' 
  AND token = '28dzvMhYFiOi5Gk1qgmnIVEOZAUtv0vb7TwNVWZmO+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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