SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7345cd490ca1ce0561ddd513b883b983eb7ebeafbf4d4696d31f671680178e39' 
  AND token = 'VvW/m2AeaxPZ83Vxwq1IICOx6JKxjT+AwhGp0JvCWDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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