SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02e5343027a2bbd2e52d4a54c77617e5f9a175032f57f980bdfb55a75c94be82' 
  AND token = '17UvLwFGxkmCrzSTJZV5DpaBEoaH+4KZTv3QEhmVp6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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