SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fa9e24de0487460241073474e9d3beaaa55f3c165f53ac0e5b1baeed422f6cc' 
  AND token = '8N41QufuPnslDMwYt6akNYEwhk5lbdhLHqlj4mIYBBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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