SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab8a35d1d092789c5f037063b8904a329e028fdeae37e7605aace859be62d948' 
  AND token = 'z6hEtgOXVkg+sOAb0DbA8UAI8ucc2e01+8PrQfQNr5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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