SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b690b45500aa3850a4f4804a6b20ecd64e8bfb9f524366149965ca7108832d2' 
  AND token = 'xnJR62xQIyajQzHccCANwZkwr3gF8ySXX16V1vPxx7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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