SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '824a77bae893083647f1f95ce33f435f979737a2b85f73b85a85affb07cfd7f1' 
  AND token = 'QkOUnv4nxwFqZHPAomlL/FYZ+I5sfknMdj5xsdtSPH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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