SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c15f770b5f41895d4a446f8d801154478ac6694d2f61c7aa609734ca73c2a12a' 
  AND token = 'mVoKa6/LOF1xBPQBFVr5AGlK+SHgw7hT/QRPuD2W9KA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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