SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e860352d1d124732df69ff75b79f4c7187ef368ac7ca3fe9df731685510402f' 
  AND token = '10RAKurERmbvBEW9BGJKLIwVMVsSSDE7HTE6AkCgp8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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