SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7004855710ddad00288f694737158a241b6f44a3a576e46c74952e0a84147e56' 
  AND token = 'b6K0pmm96zUrocRHxGoTWiHb/YauKHJVNJD2uQupOlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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