SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5250561f7f109c5518341c982dbdfd32a2136d28bc164366b9e28728e789633c' 
  AND token = 'H97PXMhpOHldiH+sSnDMRfJI5tP6WdYjgIICzvHyxHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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