SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '151ac8ee8d4effa1e97e2f343abf2917fe9499fb9fa63dbc883329522e8f57d1' 
  AND token = '8eFl8JXE17PZDDkFgpgJY9LQlihzpOSka80DpVEUlZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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