SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57bdca58667c9d8c7b000007f1f28f684d6a7eceac0fd6e4d6d8170fdf723684' 
  AND token = 'OAVVjvMlKJWt/qgF69MeAl0uOw/iwrx8vsQr9GBgvaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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