SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4241dc5c69735518b0ac77397dd8d00e4803745d2db91db9220969d88d684214' 
  AND token = 'u8Q41YlYKsWgyIhmKrKAHCnqqNbUlTHogoku9ZhjmVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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