SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2c70c267cd0f327614b21175a532788955c8578de1b271798744ccd684a1289' 
  AND token = '3V9zeSyHCE6wUQXOCAIXs9KSu0yXY/dUqkjyOdPbxnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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