SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82e14989e5bb697a234758d396501b5f9838b6bf4dd29bb7336421d4a3ed9a58' 
  AND token = 'x8nsatejYvY4iAhJHlg4GEUZNK9QZKhQVzBxj9g/mVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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