SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a0fcc6be07366a286026d1eb4d83ab093d7785e7564bece9cdb3ca1e4d2361' 
  AND token = 'ncNW2m25/4Ql5doz3r7wTQeOZehxQXkCjSzykBMnJME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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