SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cc79a4ba1d69a16b01a9f9a410d55fd903149bf535573f157450e19e2fb4eac' 
  AND token = 'Wf7G+lckYMLKgxFYwzBhjc7SZRSnmqf4S7BlRFSwdks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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