SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a6951cb8835f6eec23c22cfd8ce196676eb5ef9500db57baaf97aa260a10803' 
  AND token = '4t1IGCjlYnD4uqdZgYdg64B+C4PxHKOHzjVUmZrR5/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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