SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9f9343f2dc67da1fa91ea193c61ebba2ee2ae09aa74fe9af74b5dd7d921d5b4' 
  AND token = 'c6QBxyK7Yc7nC9TRopX+LUeaw7V3Sgh+rhXKPzCbSMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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