SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '539ce4c6ca81f19aa0fee2a91dcbbf035278e1ddcfb041042244d04c9bdae1b2' 
  AND token = 'AWJvTGrcjUT821T8GtZ+lSu7/M5UmCdS9XpnBBcMNac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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