SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '157cc687cb2966c360a8ed79cb82f5084d894b32af87269c5f771e6a161a8fb0' 
  AND token = 'jWWTXm6HgjDBs72sqLlIZApWuhLT/qIJpDTwe89lg2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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