SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1434318d29069ebfd8d011afe5bcee3b59900a8cb0618688ba37f7584a08218' 
  AND token = '5UTqwR5KSGcRwSUhcXQGK1sBO8EuD58EUgwckWBBpN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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