SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fb5e0a3031aca81a5f13c0d17725443206b48d28731321fa43405178664319d' 
  AND token = 'k0C7dRWxYedu5skBbzUryOipd/FoGJpbrCwZEObg8hY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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