SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61d5cb8ef352f0733b3ec372170e89fb83f50a85ded2e453f9c35842127197f4' 
  AND token = 'qH1osdRfL2ATOZoBlfyTXTNcIbPaDHKCuWwCQd/ev4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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