SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffce2266fcd5939ecd9c84011e4f57a2033a3ef41c3e053c5515046065c0458e' 
  AND token = 'UUm62Bkw/rQa5M/JmEY/ZSkSxwIVSxPxw5cPQkkSKzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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