SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '327d6d3117213b5c212084aaa103c4e58799fde980fcbcf48b54891bd61b3729' 
  AND token = 'h4kKNpf8xl7XRIbHDs1rNaSW9KRt/IgmaoKOZjyCAvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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