SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '914300ae3185bc19713e8696447c8d91e314a64e3647efaa78ae787286ada85b' 
  AND token = 'prNH5vdfxkoMJT2hF4g9rMeWvY6PecTT8ysBof/3dP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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