SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7789e5f0397eb51c2b2141781089fc1d09db9b7b742809c819d15b060238d5bf' 
  AND token = 'NDiboaJQDKH7O/VJ66JreC4Z+AjFiFrJ6MndzO0vZjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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