SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34cb9c1a53fa39b11c3b861c22c5adeff97eb9e0959c1a653480615c44c1a5e4' 
  AND token = 'YfnlvnwFZGErSQ6dpxrCbfVBhUMH67YgX5ui4KWtJLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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