SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3043dbd7b92876d43df943d5bbfebb3ec90910aa6df00d62e188358ed38bf37c' 
  AND token = '/UX7NjIjd+95mtRjlOhNvcggrSbqqTjQHT2rE8D/xw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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