SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b27eaad13dfeec949e93b6e08d9c4098c173deec49c9164f7483677ed465d38' 
  AND token = 'llanNe9gBadJWPddXu11nxLSjReIRUCKNOrLZm01thI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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