SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cdd0d6e66d47367b028fc2f43c04b855ce7b8be662db95f9c1ab483e300d1b0' 
  AND token = 'WWlKbc3f6zD+on7xGJfy6FDhZcoCwCOX57KlalaDwYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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