SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0492377b937242ff7448b19875b1a3af46d69536a39fe6c32ccc26e1db9e55ef' 
  AND token = 'MNlzTODB4EZsP+sHkP7TkQ+YrY9SKZOHORjgjTpX2Ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}