SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9584d77741d3789bc24e99b9ca998801a5db7d43edab10ccbf0f4b297158d6e' 
  AND token = 'Hj0oHBLGxCdPGdSBGKZvrYV5PNAf7uDXpJYjRy2QXRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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