SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '458d0ea722aec38df126ce42c5b505c97d1b67d60e6f4f7c188b9f7e94b7b8e8' 
  AND token = 'Fo6iOjZ4PiyKcAw3+mVaq8yFYsxO7YCS6oLVHZFGhdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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