SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ba0ee4eef2531f475b660e814f8d54f69fbdc17d7a8c9a8b5fe942a8faeff7d' 
  AND token = 'jca+tPTeVHIHA0vGgWxoQiP2drIZ/Alg8Fm6GuQV7Q4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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