SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '383753b3340b07bb79e5dff0b0717e174efe210d840dcc313e01b5caf44de19f' 
  AND token = 'thsqHp+FY+L444HKWtzRnsY8AbeD7dgIKhMrVoQI9G8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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