SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76d4cde026229880711465da610c324df0310085e795ea620b8150e54f63fdd7' 
  AND token = 'BUHrZaX6IBhVFLMg+Q+e7kKDcqv1aQJQeXv3V2lwcAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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