SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afdf99c9c69be748a325751a6fa12c51b02b53224e4df1f24847f79ffabaea8d' 
  AND token = 'GMpFDURyXsd4C453NsLZ9Jub0ldgqwWHILamFMcJQYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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