SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b15411a9f458bd7f7f6123cb59b3e16b9309cb1a5e014daa1a89dd434a5fc097' 
  AND token = 'DbdPSTKn8E+u07EKeRgeYZnmGrt2TMg0BEd929UxkjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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