SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eb5235606eefe1ccf9dc729451568dd29641420237b504d1f592d855b6e8b14' 
  AND token = 'KFwKNvXYJ8AobhW1AswSEXI48RVm2VRvKE+/YJlJcOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00074

JSON explain

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