SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6160dd15622f6945209f8cd5b50e209bc62569f0cb70a076d634bb02b8ea182' 
  AND token = 's6KV/RJs/AXhTJxg7eSyw/8xmS9nkIBuySkvkXYxTwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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