SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ce5c691379306c2ed258d663b058a7393c87348ec4cd1767d92bd07218134d4' 
  AND token = 'OPFtDYlcvkQjb8KpwtHMQcJZWwQiMUNywSPuR/yXg20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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