SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b868873f89924d85ee57acc336d61c19f1fdb3624f5ae4a7c302250351415f76' 
  AND token = '6hC+JSR1RRuxqeJ4NvhFMRbxIjGdOk7SKfiFp8G5qp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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