SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fb48e0fdbd9e6990bfe6d69bc7554ec373127333bbea0df87775319d1fc073f' 
  AND token = 'vmNV+B2AlzjQSDIkBYzpPUILNBuqdSOWkxjBiMB2AGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}