SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bd85d297440c6aba8bead25267e5fb0fc910b5abd050e374a5d6190871fcecf' 
  AND token = 'WnxLu1Y5TtC2TB8tH/cBY2qY/+xDN5FUe2RISwy3UHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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