SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28e8bf9a58377de8adc0f5133f8f0a7c7f4919fbc46a2daa8ef5f05dba403c82' 
  AND token = 'LKCg8MUEYaqoJq+UQy8XYs9e8sKpxADUSpZaILKydfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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