SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9d769cc938ead2528576286642faa93e8470d6f83053705c500d10acf837cee' 
  AND token = '5f2ZzGM5oIr7f5HuEzHnEw24rafwdbthYztKB3QKJeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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