SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41f21f329b240d534427332932a842ca5b5560fc35948c406e2f470be645bc63' 
  AND token = 'YSan83cPlEKGtI/kjFB+DbJ5CJsxzQS6AJyFwNRej7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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