SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6039b048bcb7c00498964cb1039c1895c15e9b6f88300ead153dd24ca023c5b8' 
  AND token = 'WqbDvMzja04wfWG/o04dLcqLrt4cwEZwGebUbeddSmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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