SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ce233f93c037a3de968781d891d5fd27b45d4a136edac4bde7d29326307f513' 
  AND token = 'BFIXsViADW3E+v0k1FLYA4D9+YY4blivS8vr+xrbpL0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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