SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f77598d53163979cc4717f6eeea5816af5823ce7d5d4378d3323ae10413d9fe' 
  AND token = 'MkbMn3Ie0QnnnEZ/u/GrH9y0ia9g9ODKScBgX6g/JiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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