SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98318eeca389c6056f674c525197540bedbf45d6251a41053d6ed1c8b12fcbbf' 
  AND token = 'i54j1wwz50wcEMtpqZTZ+auvb60hF3wE49LrZLWgZrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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