SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f36c7d55b4eead45373ded770b4d2f5c6664df05b4db1619d88a697d11afd0d' 
  AND token = 'ZTph/g4TaB3xo+AEZ8K4whi9qe7ns7t/lBSBUV2rJHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}