SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9b8c83c1b5cd112b466e362038653989c6f295a611163d87c96bc8ad53071fbb' 
  AND token = 'ROeQosAoTSXXiudQsBupvpPPnbHbufxDnpBPoCuNHUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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