SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d643083fb42f68745466b82a5475657612db50ac627b2fa054b027999853d0d' 
  AND token = 'qFrO4lzbKHEk6i5nJb+j3gJ6+g3mjQsdwBAKCwHKxcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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