SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9f4f921eb72e56d04a190baa331d94b0aa9b12dcd0dc70610983436ebd36014' 
  AND token = 'TJtlsIYBKAmlPF4KUudbIDC3W+CyU4LETwRN3lRqiYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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