SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '561e72887fde8b2eeaa63f3a59269ed4f5a0f6ee0f6c9ef4bfd24cc86b72c933' 
  AND token = 'tkJrgmos0ft98JEfMNXDQPrN6RZSHJpprEwvHwHkp68=' 
  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"
    }
  }
}