SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '326df17908f83f6328e0a5dada0f0d9697eab3527726a0624f8ecd376d839a88' 
  AND token = 'bWkb3gr0xvalxnNJyMwecSv75VFwJk0XtYINi/x4JxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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