SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24a734db3dbb8328a5f8656275bbce42991aee1046cf723332ea20e43f6c5e7d' 
  AND token = 'rfuwC/WWqQJ+hIiJiJr6EGuzi/voTsFUwpE1RfliQGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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