SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5a97af93dff6bdff708c26fc558aa658817057b0c7a44074446ebf0d0fc9928' 
  AND token = 'SSyT3O4Zv0eQCgvJsZhNw0HbxTFFbpnPtBqr54YhrbQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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