SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '620477c21a666c75b835674877616332cd97d099cf76036b33e800d7bc81041a' 
  AND token = 'xppKTkG82JhEJlJlfccMsvP450EfMwsA6ztQCv984XM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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