SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af68d4a6e5221a5664c158e55cf132f74cade543c7d0036cbe2026385aae69fd' 
  AND token = 'L/34x2JGgzuSYbRrtj55DLRLybc55nFc0T/11S1OHPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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