SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1f7cc953e285c3475f3afeaecb2d437dd3125f3dcccf35c864291600c4e2e7d' 
  AND token = 'UZN+Kt6cbK2h13Uol7WpnUvj+441uNqIIkOo3GGjZy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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