SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b34a36d953fee2063b4c87ffb3cb8f805dcac31060659433d0ded904811d217' 
  AND token = '+jJObIdKhWWthASCjaDMtcGanyZfQUFhN61cdMn9eO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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