SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad2eb74510537810e3d1efa75ac9f97dc35413af370e16b723b963c7241f7297' 
  AND token = 'Qm9aQBkBlXhDeD4u52JifJmoat0iWnevlBecg98ED7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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