SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3a6aeb14dd5fa16e5242bdedb9f87355b9e82fcacc318538473a32b479a8c67' 
  AND token = 'calt8NBWhFnMM0i1BkjRTCIfyvpBWoNYmHR/WcOjrIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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