SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1dacd4cbae7ebf8943560990700e260a3f2253eb5a43743dfb161eb91fca6b18' 
  AND token = 'lEiY+IV7KiW68I6Qyfxo3fOVhJXSU1Z4syu2hKfWFao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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