SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50ca206cadbce46e48d1643d17ed8a574c3046c93fe1948bff37a71962868d21' 
  AND token = 'jztv1AFvWYWSFViQqVm2e7MnkYvV5J6m5QHNliafbN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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