SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3944b9978e5b59e94568640fb38dd32bb10c5b630f713e289ef70a98b7a28b1' 
  AND token = 'qBMK1pF4UYJDk45YyUu/My1WQMnrUFPSyz+958EEME8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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