SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b8db266d41a644175830782f7dac421e3c314554ff38d0e0c3e8304b67d1fa4f' 
  AND token = 'v5qDTs4KDEjVJouir0tv9cNx9BunmZ9EMANKtu6tB8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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