SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59ca77525513d5e9f6847dbc4b47c4a1c7add4cda3e4b3ed4ca0ac34c1a53129' 
  AND token = 'QMUvM9LuEZziJhg0tsalcZ0YWjtVV01/MGmJ7xS41Ck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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