SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccf359c07972168d2ef2f83c10044b5e4cc048dca6fb863d7724373ede3f208b' 
  AND token = 'ZgUtHZo/hkOAx9G9PYwDMIDdCIHVIeD89sedVa1HDtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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