SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8277d226d802abb83b7fe596af1016c23c8aa0dda9747615e8aada7dbd58f367' 
  AND token = 'us8MG95iMCUd7hPnB57rVUup6YS8rRTHXLsC65VUP5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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