SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '846d8ba35172ed7352b7e837ec6f8e42921f8970a37f5a46f91d4d067e20961d' 
  AND token = 'XIQH+Y/lVzBqTqWrogKCCXcv22gX332uAPA9/xfu4MQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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