SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f0539d1e2d7e5f5f3d0247638b7b3c999dc28b5823247fb459e5be3571bc8652' 
  AND token = 'f1+zwoXUEMJ5oZs2loqX8cf6S7UhEQnDZQMnL/lVJBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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