SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e7d458208a0d9c833718111d556724ee1cdd9e948cf49f9ae5c62881f9caa5a' 
  AND token = 'sYwF69s+BE8AFGw+fDGjSbz0LfHXDCKZK9yqcxfVtG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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