SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c402638cdd2111add358d5f731938f49780187c4db7beb7f37e138c688d87c1' 
  AND token = 'ASpf635WUHD6hbV/ntUMN1pZDki5t2bN1GcIq7f++gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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