SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9b91de13f227dd28e705b658621d2cd7fd01968e030d4310ed175585174b300' 
  AND token = 'l9y0Nr9bZJHEKe9SOLY08Dc+EdqNct/5ZVhbvM9L5lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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