SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f300b892cdf35e648e7c82a80976b7d70148fde95d915f3ddca68b94b8255bc3' 
  AND token = 'TjQNug/wX+im2zgMp99SSonvA7LIWEaHCbxY22XnNeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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