SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '255fac8a3cdf85e680a3ab92d3e042159614b66a9ae074403025d5ad95659823' 
  AND token = 'QsMibHrkl/xlrxW0qwWZH8MkUTgSciGicATie/rYDBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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