SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be1b2e46fb4fb740278e4cb861b2b54d67ebb79748a7b636060734b22ab86eb6' 
  AND token = 'w9b6U0BwpS+q4QTeGTJXeYvTfb64hASLBpLDOVirkCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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