SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77ec9e7de132e4817e5cf5acc1ee2c345a897a6a3e22101b7008cbf5b4e54c4a' 
  AND token = 'ULejExtCmM1vi00lXe9LbqurS81A4xmMACTYu4rtAWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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