SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ef8e64b6651cde1c989819235a9d46107aef02f7ddd7b8581a8a33b1e53002e' 
  AND token = 'KlocVeEmgaXOZUiFA+LpPY/oWPad+qJSDa6Y/V+n2qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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