SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38019655b80d8f3159da008583a4cbebcf491e70da040bfb7bcfd6822730cbc7' 
  AND token = 'hbWfalq1FqeEJPAJU++Ng4lZmyExaSaxBsBWHoN+Org=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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