SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7413ead824475d6cc2cafff80071c7c07468ce89fb2da4a2a783cc657a4d8e20' 
  AND token = 'H4NlsDkyVS37DQLEDV1XmyuwElZ5sGxaJAE6sTH7xQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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