SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6647cc844553c6670fb8f66dff5d163c4e39f1d1fc9275499b42e268eb00808' 
  AND token = 'x21+i/hrLwZxC7FyevJ3ZlN625do2BGlI0AoKc7C7BA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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