SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc99fa7a557f4870a7666de350104239c6ebb86d58b109edd4fbc4bcadce4194' 
  AND token = '/4FbnxjkknSrdEAHp3c8RCmvtfiwZBJY9+Vv1xlfVFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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