SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2939a97dc1ebf8c0c709ff595843db2297757da97b794bb6c2073ccfb5b56dcf' 
  AND token = 'gbQcKE71dSVspDbJ0qMoPl6UrSDlMZn2IBOJaQ/Z0Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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