SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9add37ee6a93e46141fbaa51aebfdce8d6793eea4efaf90bb3cbd07dd8570fab' 
  AND token = 'QE02hk/lYgA1QL9SicibGh33zIj3rJ9JD6wNfmvlIJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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