SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc4d298049cbe44cb8b30e937f2467f256cf168265bafa10e487b2835eda96f5' 
  AND token = 'Kq2msgtor9QduV9nuJAwkkAF56l5ybc5d2YLmZYrV8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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