SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03528bb8e8ed7a4f1b3f18989223aee758e36b25fb86118647fcc4da0e0d29c7' 
  AND token = 'AbQ3cOtwuisOb9qNVRcWydOeBWGB1qBq4i0qNSia1wA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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