SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bd795202b78c1675cbd328ca416bd5259918507930b0daf4e8625fa26f8fb36' 
  AND token = '3yWMkoAiKRCEGi9qN8pE5sJAarJkxA+RaBKdWjXbCrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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