SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6b104e07b3203d3c006c4f79ae17db11a845a7df954ffb71ad3b4b74f384714' 
  AND token = 'GNKCJj4UqsTS7Wi6S4SP+GfN7OLxoe+SIYU9IWcquwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}