SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd52fe372dd26bc7b07b5572f79acf2f1496cd1bf26a98e5fe549a72fe8b48d7' 
  AND token = '+FpGzgO1asr7KghNkwJv6q37GII1oi18kttYs4zDHh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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