SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ff0d85c79b00ccd304849b29d269905106e1d30360be55da17e461d80e09745' 
  AND token = 'aeHy1U1x7eDI24SB8qg06rwMzKFKajdNSWine/MM6Bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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