SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bbc331b6c508e66cd763856a900f1132a1c5a940fbdbb09654a385cb02da43e' 
  AND token = '2NYU8LLiVENpcWBesIg3W9UjPm8fjI56y8bkUYUsd58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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