SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15abc90694cdbf50ab4de67362df57de2197e1012896d8d74753baf32f8ddb72' 
  AND token = 'Wsll5C8dNkX9UcHrhpwqlhgrIRIii5J3NmMKU8/BvX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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