SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98de8c34bc7e3c11fb93b0873253017111eca3a2eb14016d183a1e00ed01a0e1' 
  AND token = 'jOrmHjAsydvHh2YoSF3JpGSkWbUkJgEVlWbi35iWSI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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