SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cb6418af148ed208b78b9d0adf47682668035d7cb62cc6006267e9a1940dbe36' 
  AND token = 'yAd8L77iok1DIMkG760aGn5S71oppX9q+SwtsT+R4Uc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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