SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93b6bf47ff6dc2475da0556725451bc4d366e9dbd63bdcd20f280828ccaff301' 
  AND token = 'zvnZNeXUnKKA+xJ8YLiXijRYFsYRaKgciiylAPJ1ZYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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