SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e71b946c56738b55ee398a418d57bae475e805d91baec143cdf7a531fe3128a' 
  AND token = '7S9DDdBPfspYKEwrpVepzuXX9qAND08KRTkuLY4qNGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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