SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cda37d58eef7a36a95ac1f95df01252d87239af6bdb7d61d880a81efe134aa4a' 
  AND token = '2tZlg+ghTfV1MXJ/gY/w+SQaDK6XMrjzHmbwLTDAfvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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