SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7da7fab02aab59600f2dc7dd39218021a9eb1aeda8fb284a1e1abbd293f346f0' 
  AND token = 'eU0dcDEdbJ4I3z1KBBOg8mBOnYWqJH0WlhBq3UfzTfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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