SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd217f4599da24509e87be4ec8c2047940048a5a97ab2100edee738388531d148' 
  AND token = 'l6VUb/xdTAYtFLnlO43XgjjLi5UKVE8DW28GRyefF/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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