SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bb6ad4b87e5034107c8d79b4f7245c23e1b4e6183e0594eeeb7301d6cdb9478' 
  AND token = 'mDJB7j2SOqU1ztrKKwczFhKJ6uyC1YvUSJslXkx+U3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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