SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e69420853a8759487235c33defc503ff7c119604752bd809af21a6354804c812' 
  AND token = 'SDJM/zPBKcCV3Qn8S5eF0V+JyqN1GXSMW5Kt6Z7s8YQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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