SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9d408a446221d9f26a463b459fdce7349477d4d597368f8104f1b6fb6e895b9' 
  AND token = 'ZJveRvPZrNbx1klxcwZzBXNNdnDlzNGoltFfCQezXQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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