SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dd294a6d050f7bbad8317602b29d8a3ca501df88db40035957ba958f92a0f0f' 
  AND token = 'gsb+/jo6n6Qds+v3UAfk59F821eaFihnj7V4G1oMNlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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