SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd98eb6935e6381eacb8d875f552499cc8c66f4f160275e401e812b97d968c085' 
  AND token = 'KLnaOMCRAgIlnj4sHVCJCb/+4bGwLNsU70HLim4AXEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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