SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c06a37d0bf63bf931e8f1a0d12aa7e65a6f7dd5339e002f322c93975fd8f65c0' 
  AND token = 'dfqMVtCg/OP8uWYF63LTbBXZGLmMQWqBZ8p1tU8Ez0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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