SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '640cf00347d85fd3170106cb088f320df13875265a2e5e06c97d2401d66a292c' 
  AND token = 'nFDH+act4CJzPDJ1OmJPQ8aivxlLFdlCuuEefWyIspg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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