SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fc8122d033ec5e6b2483648bcfe134aeaec82904ceeeb9810bc8e0ad4ce944d' 
  AND token = 'IM2DAgnAdi/8bAfJoBoC5JJ1xqCPhflGQSYdejdCk8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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